android/gatt: Fix handling advertising state
android/gatt: Fix handling advertising state

This patch fixes enabling advertising.
It was not possible to enable it if we had server registered
which is on listen_apps list but does not trigger advertising.

This patch introduces static counter to track number of clients
requested advertising.

silent-snowman/bluez,ComputeCycles/bluez,pkarasev3/bluez,mapfau/bluez,ComputeCycles/bluez,ComputeCycles/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,pkarasev3/bluez,silent-snowman/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,silent-snowman/bluez,mapfau/bluez,mapfau/bluez